The invention relates to a frequency converter comprising a processor and a memory. Frequency converters are generally used in connection with electric motors.
An entity formed of a frequency converter and an electric motor is often incorporated into a surrounding system that gives commands to the frequency converter and may receive response signals from it. To be incorporated into the surrounding system, the frequency converter comprises software. The software is usually stored in a non-volatile memory. It controls the processor to implement the basic functions of the frequency converter in response to input signals coming from outside. The basic functions can be considered to include the critical tasks in respect of the electric motor, such as starting, switching off and speed control of the motor as well as possible fault and/or safety control. In addition to speed, the controlled variables may include frequency, torque, location and power. In inverter use, there may be other controlled variables as well. With respect to this invention, the only essential thing is that the frequency converter has given basic functionality provided by the manufacturer and generated by a processor in the control of basic software. Defining the basic functionality in detail is not essential from the viewpoint of the invention.
The general tendency towards large production runs necessitates standard frequency converters with standard basic software, irrespective of the customer or application. On the other hand, the basic software of a frequency converter is not necessarily applicable to be incorporated into the surrounding system. For example, the signalling protocol (command language) of the surrounding system may be different from that of the basic software of the frequency converter.
It is not probable that the supplier of the surrounding system would like to customize its own command language. Thus, a protocol converter is required to adapt the frequency converter to the surrounding system. If the protocol converter is a separate device or an accessory card with processors, this means a significant increase in the costs. On the other hand, if there is no protocol converter or if it is integrated into the frequency converter or the surrounding system, the frequency converter or the surrounding system have to be manufactured case-specifically, which makes long production runs impossible.